1. Field of the Invention
The present invention relates to a passive safety device that inflates a portion of the webbing for binding an occupant on a seat with high pressure gas supplied from an inflator when a vehicle collides.
2. Description of Background Art
An air belt system for an automobile that houses a bag inside the webbing of a seat belt and softly binds an occupant by inflating the bag when a vehicle collides is disclosed in Japanese published unexamined patent application No. Hei 11-348720. For this air belt system, the volume when the bag is inflated is minimized by thickening the thickness when a shoulder belt for binding an occupant is inflated in an intermediate portion that comes in contact with the front of an occupant. In addition, the shoulder belt is thinner at the upper and lower ends that come in contact with the neck and the side so as to reduce the required capacity of the inflator.
The conventional type air belt system has a main object to bind the front of an occupant in a head-on collision of a vehicle. However, since the upper end of the bag is thin, it is difficult to effectively bind the head and the neck of an occupant in a side impact. Therefore, to protect the head and the neck of the occupant in a side impact, a side air bag system and an air curtain system are required to be provided in addition to the air belt system. However, when the side air bag system and the air curtain system are provided in addition to the air belt system, the cost is not only greatly increased but it may be difficult in a compact vehicle to secure the space for mounting the side air bag system and the air curtain system.
The present invention overcomes the above-mentioned disadvantages and it is an object of the present invention to enable effectively binding of the front, the head and the neck of an occupant in a vehicular passive safety device that binds the occupant by inflating the webbing.
To achieve this object, according to the present invention, a vehicular passive safety device is based upon a vehicular passive safety device that inflates a portion of the webbing diagonally arranged on the front portion of an occupant to bind the occupant on a seat with a high pressure gas that is generated by an inflator when a vehicle collides. An upper portion of an inflated portion of the webbing is located in a position in which each side of the head and the neck of the occupant can be protected with a shape that is proposed.
According to the above-mentioned configuration, as the upper portion of the inflated portion of the webbing that is diagonally arranged on the front of the occupant is located in a position in which each side of the head and the neck of the occupant can be protected with a particular shape, it is needless to say that the front of the occupant can be softly bound with the inflated portion in a head-on collision. The inflated portion enables the head and the neck of the occupant to be softly bound with the inflated portion in a side impact and the webbing of the passive safety device can also function as a side air bag system and an air curtain system.
Also, according to the present invention, a vehicular passive safety device includes a thickness wherein a portion to be inflated of the webbing that is inflated is proposed to become thinner from an upper portion to a lower portion based upon the configuration disclosed in the present invention.
According to the above-mentioned configuration, as the thickness when the portion to be inflated of the webbing is inflated becomes thinner from the upper portion to the lower part, the required capacity of the inflator can be reduced by thinning the lower portion of the portion to be inflated wherein a required binding force can easily be acquired even if the thickness is reduced, enabling secure binding of the head and the neck of the occupant with the upper portion of the inflated portion and reducing the volume.
Also, according to the present invention, a vehicular passive safety device according to the present invention includes portions of the two webbings to be inflated that are diagonally crossed on the front face of the front of an occupant based upon the configuration according to the present invention.
According to the above-mentioned configuration, as the portions of the two webbings to be inflated are diagonally crossed on the front face of the front of the occupant, the head and the neck of the occupant can be not only softly bound in a side impact from a right or left direction but the head can be securely bound in a head-on collision and the chin can be prevented from coming in contact with the front. In addition, as the portions of the two webbings to be inflated become thinner downwardly, the portions to be inflated can be smoothly crossed.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.